R. & M. Monteverde Pty. Ltd. is Queensland’s oldest and most experienced underpinning contractor, with over fifty years of experience in a wide range of commercial, industrial and domestic projects. Our company is fully licensed, with skilled and qualified staff who are experts in solving difficult foundation and masonry problems. The companies two directors, Ron Monteverde is a registered open builder and Robert Monteverde is a registered open house builder.
We are skilled in a variety of underpinning and restoration techniques, including mass pads, drilling, bored piles, jacked piles, screw piles, grout piles, pressure grouting and lime stabilisation with the company undertaking approximately 150 projects annually throughout Queensland and Northern N.S.W.
Underpinning is the process of supporting the footings of an existing building at a greater depth. Underpinning is often necessary where the quality of the original soil is poor. The original founding material may be of poor quality because:-
If there is damage in your building in the form of:
Then you may have a foundation problem that could be corrected by Underpinning.
The first step is to contact us to discuss your problem, after an inspection we can put you in contact with one of several experienced engineers to determine the cause of the movement or damage. They may well recommend Underpinning to correct the problem.
Our company is committed to providing consistent quality in our services, including:
We are concerned that both our immediate customers and product end-users all benefit from the quality of our work.
We are fully aware of all current legislation including Workplace Health and Safety for which we have regular training meetings. We are a Quality Assured Company, which is audited annually by independent auditors. All our work is lodged with registered private certifiers for approval.
R. & M. Monteverde Pty Ltd is a member of the Queensland Master Builders Association from whom we receive regular updates regarding changes in legislations, building codes and new innovations etc. We also receive regular correspondence from Building Services Authority regarding industry trends, changes in contract documentation and all relevant building code changes that are important in the building area.
This is where a Pad, or a pit is dug under the existing footing which can be any where up to 2 metres long, 1 metre wide and 2 metres deep. This is normally dug by machine or by hand if there is not enough room for a machine. The pad is dug further under the existing footing to the width of that footing.
Once the required depth is reached, as per the engineers report, concrete is poured leaving a void between the new concrete footing and the old footing. This void is where a jack is placed for jacking to bring the walls of the building as close to original level as possible. Once the building is jacked to as close as original level the void is packed with dry pack grout and the pit is backfilled.
This is perhaps the most popular form of underpinning as it allows you to drill down to great depths to find bearing capacity, as per engineer specifications, for new footings. We have the capability to drill piers from 75mm to 750 mm in diameter and up to 10 metres in depth with our vast array of machinery. We have drilling rigs to suit all conditions from commercial drilling machines to portable rigs that can be used inside restricted areas when ceilings are as low as 1.8 metres, for example, inside your home. These portable rigs have the capability of drilling down to a 6 metre depth.
Firstly, a small pit is dug to a depth of 600 – 700mm below the bottom of the existing footing. Then we proceed to drill to the required depth as per your engineer’s specification. Once we are at the required depth we will dig under the existing footing to the width of that footing.
A steel reinforcing cage the depth of the pier is then placed down the pier with another cage known as a headstock joined from the top of the cage to underneath the existing footing. The pier is then filled with concrete which covers the headstock. A void is left between the top of the headstock and the bottom of the existing footing. This void is where a jack is placed for jacking to bring the walls of the building as close to original level as possible. Once the building is jacked the void is packed with dry pack grout and the pit is backfilled.
Jacked Piles is a method of underpinning for use below footings founded on weak fill spoil overlaying strong stratum, hard clays or weathered rock. This form of underpinning is particularly suitable for limited access situations where there is no room for drilling rigs of any capacity. The depth attainable by these jacked piles is directly related to the proof loading the building can sustain. It is not recommended for residential housing as this method relies on the weight of the building to reach the required loading capacity.
A pit known as a headstock is dug to a depth of 1300mm below the existing footing. The width of the headstock is the width of the existing footing.
Steel pipes of 1 metre length ranging from 170mm – 300mm in diameter are then driven down via a hydraulic jack. These metre length pipes are welded together until the required depth, as per your engineers report or the proof loading, is reached. Once that depth is reached, the pile is concrete filled and steel reinforced if required. An RSJ is welded to the top of the pipe and then 2 steel pipes are welded from the RSJ to a steel plate that is bolted into the existing footing which gives the existing footing and the building the support it requires.
The pit is then filled with concrete and backfilled.
This method of underpinning is particularly effective in unstable soils, particularly sand, moist and highly reactive soils and works similarly to the theory of the bored piers. After the pit is dug, galvanised steel piles are screwed into the ground using a machine specially designed for this purpose to the depth required as per your engineer’s specifications.
These piles can attain a depth of up to 15 metres. The centre of the steel pile is then filled with concrete and as with the bored piles, the top is then tied into the headstock. The headstock is then covered with concrete. A void is left between the top of the headstock and the bottom of the existing footing. This void is where a jack is placed for jacking to bring the walls of the building as close to original level as possible. Once the building is jacked the void is packed with dry pack grout and the pit is backfilled.
These piles can also be used as a method of support for new structures and slabs.
Grout Piles are the ideal solution when the failed footings are located in sand. The theory is very similar to bored piers but unlike bored piers when the augers are removed from the ground the pier is prone to collapsing because it is drilled in sand. With this method we can drill piers to a depth of 10 metres with a diameter of 450mm. As with bored piers we dig a pit 600mm – 700mm below the existing footing with the width of the pit being the width of the existing footing.
There is difference between the augers that we use for grout piles and bored piers. The difference is the augers used for grout pile have a hole with a 100mm diameter running down the centre of the auger. After we have achieved the required depth for the pier, as per your engineer’s specifications, we place a hose in the hole down the centre of the auger. Before removing the auger from the hole we pump what is know as acquagel down the auger. This process firms up the side of the pier and stops the sand from collapsing. Once the acquagel reaches the top of the pier we then pump grout through the hoses while the augers are being withdrawn.
After this procedure we drive the steel reinforced cage into the grout for extra support. The procedure then follows the standard of tying a steel headstock from the top of the cage to underneath the existing footings. One the grout is set we pour concrete into the pit leaving a void between the new concrete and the existing footing for jacking purposes.
One sure sign that your home may require underpinning is when you can see cracks in your brickwork or internal walls. This is caused from movement in certain areas of the existing foundation while other areas may not be moving thus parts of your walls will separate and leave gaps.
Once the underpinning process is complete and the concrete has had time to settle, which we normally allow a minimum of 7 days, we will come back and jack your building where we have completed the underpinning.
This is done by placing hydraulic jacks between the new footings we have created and your existing footings. These jacks have the capability of moving a 50 tonne capacity. We do not jack from one pin alone e.g. if we have done 10 new pins, we will use 10 jacks for the process therefore creating an equal and smooth lift.
We always attempt to jack your home or building back to its original level, trying to close up all the cracks but sometimes this is not always possible as your original footings may be weak and brittle and may not be able to handle the pressure from the new stable footings we have created.
Once your house or building is back to original level or as close as possible to that level, the jacks are removed and steel plates are inserted into the void for support and the void is then packed with dry pack grout to stop any movement between the old footing and the new pin.
Pressure Grouting is used when the soil under your existing slab subsides which leaves a void between your floor or slab and the ground below it. This void sometimes leaves cracks in your floors, can cause doors and windows not to open and cause visible gaps between the floor and door frames.
The process of Pressure Grouting involves the injection of cement/fly ash grout into the voids to fill that gap which provides support to the slab. This is achieved by drilling holes into the slab at spacings of 1.5m to 2.5m, depending on the size of the slab. Nozzles are then placed into these entry points and then the cement/sand grout is pumped via hoses through the nozzles underneath the slab.
This process is used to stop any further subsidence of the slab. The re-levelling of the slab can sometimes be achieved provided a seal can be maintained around the perimeter of the slab.
A major cause of foundation movement is when moisture reacts with the clay around your existing footings. It can also cause movement to any slabs or paths that are laid around the perimeter of your home. The process of using a moisture barrier is predominately aimed at remedial works for the distress caused by this moisture.
The process involves digging a trench to a depth anywhere between 600mm to 2 metres, depending on your engineer specifications, and is normally 200mm wide. Once the trench is dug layers of Micron PVC are placed down the inside of the trench on the side closest to your dwelling. This Micron PVC also covers the ground between the trench and your dwelling allowing you to replace any slab or concrete path that has been effected by movement.
Once the Micron PVC is in place the trench is filled with concrete. Your engineer will specify that a slab is to be laid next to your dwelling that becomes the moisture barrier. This slab along with the micron PVC prevents any moisture from seeping into your existing footings which may cause movement.
Another cause of foundation movement is tree roots. Underground roots can grow towards your foundations and suck all the moisture content out of the soil around your footings causing these footings to fail. The roots can also cause your plumbing pipes to break releasing moisture into the soil around your foundations.
If this issue is detected early it may prevent from having to underpin your property.
The concept of a root barrier is very similar to that of a moisture barrier. The process involves digging a trench to a depth anywhere between 600mm to 2 metres, depending on your engineer specifications, and is normally 200mm wide. Once the trench is dug layers of hard plastic, known as root barriers, are placed down the inside of the trench on the side closest to your dwelling. The trench is then filled with a substance called Bentanite. This plastic along with the bentanite is so durable that it prevents any tree roots passing through it, diverting their growth away from your footings.
We have been carrying out lime stabilisation since 1985 throughout Queensland and Northern New South Wales. This process is predominately aimed at remedial works for distress. During this period, experience has allowed for the development of the lime stabilisation process where it can be offered as an effective and cost reduced alternative to other forms of work such as Underpinning.
The process of the work is very similar to pressure grouting with lime as opposed to grout being pumped into the area required.
The addition of small qualities of lime to expansive clays will reduce the plasticity of the soil and its swelling potential. Lime drastically reduces the expansive potential of clay soils. Expansion of soil is a major factor in foundation movement which most times will lead to the requirement of underpinning on your property.
Over the years we have developed many different types of machinery for various projects we have undertaken.
We now have machinery that is capable of drilling for both commercial and residential projects.
These machines are capable of drilling to whatever depth your engineer requires with piers from 200mm to 750mm in diameter.
We have machinery that can work inside your home needing only a clearance of 1.8 metres in height, we even have small ride on drilling rigs that can work inside your garage and get to places where our larger machines cannot go. The advantage of these machines is that we can have your job finished a lot quicker than our competitors can.
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